You cannot upload files to the server in mobile Safari 8.0

Sad but true. The new version of iOS contains a bug that makes it impossible to send any files to the server from the browser. When you select a file in any form on an HTML page and try to send it, the browser sends a request without a file. It shows that it is waiting for a response to the request, but in fact the answer does not come.

Moreover, the bug concerns not only HTML forms. If you send a file from Javascript constructing an object FormData(part of the XMLHttpRequest Level 2 API), this produces the same result. And even if you do the same from a native application, which is a wrapper over an HTML browser (for example, Apache Cordova), you get the same result.

Why does not the answer come. If the file simply did not send, we could expect that an empty file would come to the server or the server would return an error that the form was submitted without a file. However, the server simply does not send any response (even 400 bad request) and does not close the connection. The thing is exactly which request sends Safari.

POST /form/ HTTP/1.1
Host: 192.168.5.59:8000
Referer: http://192.168.5.59:8000/
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryGVP84V9BXQSqpZw2
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Content-Length: 134573
Accept-Language: ru
Origin: http://192.168.5.59:8000
Accept-Encoding: gzip, deflate
Connection: keep-alive
User-Agent: Mozilla/5.0 (iPhone; CPU iPhone OS 8_0 like Mac OS X) AppleWebKit/600.1.4 (KHTML, like Gecko) Version/8.0 Mobile/12A365 Safari/600.1.4
------WebKitFormBoundaryGVP84V9BXQSqpZw2
Content-Disposition: form-data; name="file"; filename="image.jpg"
Content-Type: image/jpeg
------WebKitFormBoundaryGVP84V9BXQSqpZw2--

It can be seen from the headers that the file sending request must have a length of 134573 bytes (Content-Length header), but in fact the body of the request is missing the file body, which is why the real request length is 176 bytes. As a result, the server waits for the browser to send the missing 134397 bytes, and the browser thinks that it has already sent the entire request and is waiting for a response from the server. Neither of these will ever happen and the connection simply closes by timeout.

The bug appears in Safari 8.0 (build 600.1.4) under iOS 8.0 (build 12A365). Interestingly, under the iOS simulator, which comes bundled with Xcode, this bug does not appear, although the build numbers are the same there. However, on real devices (iPhone 4S, iPhone 5, iPad 3 were tested), the bug always plays. We hope that the bug will be fixed in the next minor update.

If someone wants to see the error himself or try other devices.

The debugger in Safari is useless here, because in any case it shows the request body without the contents of the files. Because an error directly in working with HTTP, making an online example is quite difficult. I haven’t come up with anything smarter than starting netcat and sending requests to it. Here is the instruction:

1) Run netcat -l 8000on a computer in the same wi-fi network with the device.
2) Do the simplest form on jsbin or jsfiddle :

<formaction="http://192.168.5.59:8000/form/"method="post"enctype="multipart/form-data"><inputtype="file"name="file"><inputtype="submit"></form>

Where 192.168.5.59 is the ip address of the computer where netcat is running.

3) Open the bin or fiddle on the device. Choose any file, send.
4) Look at the output of netcat.

If the answer is similar to the one in the article, then the bug is present. If the contents of the file are before the last line, then no.